Process for manufacturing a waterproofing assembly of laminated bituminous roofing membranes

Abstract

A novel self-adhesive type multi-layer laminated bituminous roofing membrane suitable for the formation of the roofing or waterproofing layer on roofs, floors and the like is provided. It comprises a base sheet of a sheet-like material, one or more bitumen layers coated on all or part of one or both faces of the base sheet, at least one layer of compound bitumen including both bitumen and rubber and/or resin laminated on all or part of the surface of said bitumen-coated layer on the base sheet and at least one release sheet laid over the whole surface of said compound bitumen layer. This roofing membrane is produced by uniting the bitumen-coated base sheet and the compound bitumen-coated release sheet, and can be applied over a substrate in a simple manner, without the step of melting or liquefying bitumen as in the conventional application process.

What we claim is: 
     
       1. A process for manufacturing a built-up bituminous roofing or waterproofing assembly, utilizing a self-adhesive, multi-layer, laminated, bituminous roofing membrane, comprising a flexible base sheet having on at least a portion of one surface thereof a first surface coating layer of uniform thickness applied in direct face-to-face mutually adhering contact therewith, said first surface coating layer consisting essentially of a substantially solid, waterproofing roofing bitumen; a second surface coating layer of uniform thickness superposed on said first layer and having its inner surface in direct, face-to-face, mutually cohering contact with the outer surface of said first surface coating layer, said second coating layer being of lesser thickness than said first coating layer and consisting essentially of a compound bitumen containing from about 5 to 95 percent by weight of substance selected from the group consisting of rubber, thermoplastic resin and mixtures thereof, said compound bitumen being of high tackiness at ambient temperature and being self-adhesive to the compound bitumen layer of another like roofing membrane; and a release sheet having a release surface in direct face-to-face releasably adhering contact with the outer surface of said second coating layer, comprising the steps of a. laying a plurality of said roofing membranes over a substrate so that said membranes partially overlap,   b. removing the release sheets from the roofing membranes to expose the second layers thereof,   c. placing said second layers in direct face-to-face contact and pressing said second layers together to form a waterproof joint therebetween.   
     
     
       2. A process as claimed in claim 1 including the steps of applying additional roofing membranes over said plurality of roofing members and repeating steps (b) and (c) to form waterproof joints between all the membranes. 
     
     
       3. A process as claimed in claim 2 in which said additional roofing membranes are applied so that each joint between said plurality of membranes lies between the marginal edges of at least one of said additional membranes so as to be covered thereby.